The invention relates to a device for the detection of a foreign body as for instance a thread or a wire in a coin channel or the recognition of the edge mill of coins moving along the guide channel.
Automatic vending machines or gambling machines may be tampered with by inserting a coin hanging on a thread into the coin slot so that the coin can be pulled out with the thread as soon as the coin has caused a signal for a genuine coin to be produced so that goods are supplied or some operation in a game enabled.